(average; United States dimensions)A typical postage stamp measures an average of 800,000 circular mils. One of the most prized stamps among collectors is the US-issued "Inverted Jenny" stamp printed in 1918, which features an upside-down image of Curtiss JN-4 ("Jenny") airplane; a single stamp sold for $977,500 at a 2007 auction.

(United States quarter-dollar coin) (a.k.a. Quarter dollar, a.k.a. Washington quarter, a.k.a. two bits)The George Washington quarter, in circulation in various forms since 1932, has a diameter of 24.26 mm (0.955 in) and an area of 912,200 circular mils.

In other words, 912,200 circular mils is 1.620 times the size of a Penny, and the size of a Penny is 0.6170 times that amount.

(United States one-cent coin) (a.k.a. Lincoln penny, a.k.a. Cent, a.k.a. One cent piece)The Lincoln penny, in its current design since 1909, has a diameter of 19.05 mm (0.75 in) and an area of 562,000 circular mils.

In other words, 912,200 circular mils is 5.9460 times the size of a Nailhead, and the size of a Nailhead is 0.16820 times that amount.

(for 11-gauge wire nai)
An 11-gauge nailhead measures 153,400 circular mils. Nails have been used since ancient times; archaeologists have discovered Ancient Egyptian nails that are over 5,000 years old.